<template>
  <div class="subject">
    <span>{{num1}}</span>
    <span>+</span>
    <span>{{num2}}</span>
    <span>=</span>
    <input type="number" v-model.number="result" :disabled="isAble" /> &nbsp;
    <button @click="add">提交</button>
  </div>
</template>

<script>
export default {
  props: ['index'],
  data(){
    return{
      num1:Math.floor(Math.random()*10),
      num2:Math.floor(Math.random()*10),
      result:null,
      isAble:false
    }
  },
  methods:{
    add(){
      this.isAble=true
      let str=(this.num1+this.num2)===this.result?'正确':'错误'
      this.$emit('addFn',str,this.index)
    }
  }
};
</script>

<style scoped>
.subject {
  margin: 5px;
  padding: 5px;
  font-size: 20px;
}
.subject span {
  display: inline-block;
  text-align: center;
  width: 20px;
}
.subject input {
  width: 50px;
  height: 20px;
}
</style>